US20240138033A1 - Electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette and driving method thereof - Google Patents
Electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette and driving method thereof Download PDFInfo
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- US20240138033A1 US20240138033A1 US18/345,826 US202318345826A US2024138033A1 US 20240138033 A1 US20240138033 A1 US 20240138033A1 US 202318345826 A US202318345826 A US 202318345826A US 2024138033 A1 US2024138033 A1 US 2024138033A1
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 106
- 230000005674 electromagnetic induction Effects 0.000 title claims abstract description 49
- 239000003571 electronic cigarette Substances 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title description 20
- 239000003990 capacitor Substances 0.000 claims abstract description 14
- 230000008859 change Effects 0.000 claims description 85
- 239000010752 BS 2869 Class D Substances 0.000 claims description 24
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Images
Classifications
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- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
- A24F40/46—Shape or structure of electric heating means
- A24F40/465—Shape or structure of electric heating means specially adapted for induction heating
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/06—Control, e.g. of temperature, of power
- H05B6/08—Control, e.g. of temperature, of power using compensating or balancing arrangements
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/20—Devices using solid inhalable precursors
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/50—Control or monitoring
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/50—Control or monitoring
- A24F40/51—Arrangement of sensors
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/50—Control or monitoring
- A24F40/57—Temperature control
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
- A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
- A24F40/90—Arrangements or methods specially adapted for charging batteries thereof
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/211—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
- H03F3/2173—Class D power amplifiers; Switching amplifiers of the bridge type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
- H03F3/2176—Class E amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
- H03F3/2178—Class D power amplifiers; Switching amplifiers using more than one switch or switching amplifier in parallel or in series
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B1/00—Details of electric heating devices
- H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
- H05B1/0202—Switches
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/04—Sources of current
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/06—Control, e.g. of temperature, of power
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
- H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
- H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
- H05B6/108—Induction heating apparatus, other than furnaces, for specific applications using a susceptor for heating a fluid
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2220/00—Batteries for particular applications
- H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/391—Indexing scheme relating to amplifiers the output circuit of an amplifying stage comprising an LC-network
Definitions
- One or more embodiments of the present disclosure relate to an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette using a heat-generating body and a driving method thereof. More specifically, one or more embodiments of the present disclosure relate to an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette, which can maximize a power utilization factor in a process of heating the aerosol-forming article of the electronic cigarette using the heat-generating body, can reduce the implementation and manufacturing difficulty of the apparatus, and can adaptively control a heating temperature of the heat-generating body and a driving method thereof.
- the metal heat-generating body may be implemented to have various shapes by using metal objects such as a heating blade, a heating spear, and a heating can.
- an electromagnetic inductive heating method using heat generation characteristics corresponding to power loss by generating eddy currents in order to increase the temperature of the heatable metal heat-generating body.
- an AC magnetic field is generated in an LC-type resonant network including an inductor to raise the temperature of the metal heat-generating body, and the aerosol-forming article in contact with the metal heat-generating body is heated to the temperature at which volatile components are released.
- the metal heat-generating body may be implemented to have various shapes by using a metal component, similar to the resistive heat-generating body.
- the heat-generating body should physically contact the electronic apparatus; whereas, according to the electromagnetic inductive heating method, the heat-generating body can be heated when the heat-generating body is physically in contact with or not in contact with the electronic apparatus.
- the electromagnetic inductive heating method as described above can quickly raise the heat-generating body to a target temperature compared to the resistive heat generation induction method, and can provide users with high usability when using limited power through a relatively high power utilization factor.
- FIG. 1 is a diagram illustrating a class-E power amplifier structure published in Korean unexamined patent application publication No. 10-2020-0003938.
- Korean unexamined patent application publication No. 10-2020-0003938 uses an amplifier power with class-E structure for the rapidity of heating and the formation of a small-sized apparatus.
- the class-E power amplifier includes an LC load network that includes a series connection form of an inductor and capacitor and operates with only a single switch, the class-E power amplifier is suitable for the formation of a small-sized apparatus.
- the class-E power amplifier is a power amplifier that operates in a switch mode, it is suitable for electromagnetic induction heating compared to other linear mode power amplifiers and is thus effective in forming aerosol by rapidly heating a heat-generating body.
- the class-E power amplifier has a very high drain-to-source peak voltage across the switch (reference numeral 1320 in FIG. 1 ) due to the structure and operation characteristics thereof, and thus a switch element with a high breakdown voltage is necessarily required. This will act as a very large barrier to restrictions on the use of parts and increase in unit cost in implementing the device.
- the class-E power amplifier since the class-E power amplifier has peak-shaped current waveform characteristics along with the high drain-source peak voltage, it has a disadvantage of lowering a power utilization factor of the power amplifier.
- the power utilization factor of the class-E power amplifier is very low at approximately 0.0981, which can be attributed to numerical values of a high peak voltage of approximately 3.56 and high peak current of approximately 2.86 applied to the switch.
- the electromagnetic induction heating apparatus using the class-E power amplifier requires a user to repeat a charging process, especially in an application field (e-cigarette in a narrow sense) that uses a limited voltage and current source (battery or capacitor).
- the electromagnetic induction heating apparatus using the class-E power amplifier requires a switch having) a breakdown voltage several times higher than (normally approximately 3.56 times, as high as approximately 7 times) the voltage source used to ensure stable operation of the apparatus, the difficulty of implementing the apparatus is very high.
- PTL 1 Korean unexamined patent application publication No. 10-2020-0003938 (published date: Jan. 10, 2020, Title: Induction heating device for heating aerosol-forming base material)
- One or more embodiments of the present disclosure provide an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette, which can maximize a power utilization factor in a process of heating the aerosol-forming article of the electronic cigarette using a heat-generating body, can reduce the implementation and manufacturing difficulty of the apparatus, and can adaptively control a heating temperature of the heat-generating body and a driving method thereof.
- the driving unit may be configured to limit the operating frequency of the switch unit of the power amplifier to an inductive susceptance frequency region lower than a resonance frequency of the parallel-structured LC resonant network.
- the amount of current of the resonant inductor is inversely proportional to frequency in the inductive susceptance frequency region.
- the power amplifier may be a current mode class-D power amplifier, and the switch unit constituting the power amplifier may be configured to induce resonance of the parallel-structured LC resonant network to transfer power to the heat-generating body.
- the power amplifier may further include a first choke inductor, installed between a drain of a first transistor switch constituting the switch unit and the power supply unit, and a second choke inductor, installed between a drain of a second transistor switch constituting the switch unit and the power supply unit.
- the parallel-structured LC resonant network may be connected to the drain of the first transistor switch and the drain of the second transistor switch.
- the driving unit may be configured to estimate a change in temperature of the heat-generating body by calculating a change in resistance value of the heat-generating body according to a voltage of the parallel-structured LC resonant network, and control the operation of the power amplifier according to the estimated change in temperature of the heat-generating body.
- the driving unit may be configured to adjust output power of the power amplifier including the parallel-structured LC resonant network by varying the operating frequency of the switch unit in response to the estimated change in temperature of the heat-generating body.
- the driving unit may include a sensing circuit configured to sense a voltage of the parallel-structured LC resonant network, an MCU configured to estimate a change in temperature of the heat-generating body, by calculating a change in resistance value of the heat-generating body according to the voltage of the parallel-structured LC resonant network sensed by the sensing circuit, and generate a heat-generating body temperature control signal for controlling a temperature of the heat-generating body according to the estimated change in temperature of the heat-generating body, and a switch driver configured to generate a switch driving signal for differentially driving the pair of transistor switches constituting the switch unit according to the heat-generating body temperature control signal received from the MCU.
- the driving unit may be configured to calculate a change in resistance value of the heat-generating body according to a current used by the power amplifier and control the operation of the power amplifier according to the calculated change in resistance value of the heat-generating body.
- the driving unit may be configured to actively control an amount of power transferred to the heat-generating body by controlling the temperature of the heat-generating body using an impedance change characteristic that changes according to a change in frequency of the parallel-structured LC resonant network.
- the driving unit may include a sensing circuit configured to sense a current used by the power amplifier, an MCU configured to calculate a change in resistance value of the heat-generating body according to the current used by the power amplifier sensed by the sensing circuit and generate a heat-generating body temperature control signal corresponding to an impedance change characteristic due to a change in frequency of the parallel-structured LC resonant network, in order to control a temperature of the heat-generating body according to the calculated change in resistance value of the heat-generating body, and a switch driver configured to generate a switch driving signal for differentially driving the pair of transistor switches constituting the switch unit according to the heat-generating body temperature control signal received from the MCU.
- an operating frequency of the pair of transistor switches constituting the switch unit may be approximately 0.1 MHz to approximately 27.283 MHz.
- the power supply unit may include a rechargeable DC battery.
- FIG. 1 is a diagram illustrating the structure of a class-E power amplifier published in the prior art
- FIG. 2 is a block diagram conceptually illustrating an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette in accordance with one or more embodiments of the present application;
- FIG. 3 is a circuit diagram of the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette in accordance with one or more embodiments of the present application;
- FIG. 4 is a diagram illustrating an example in which a heat-generating body is included in one or more embodiments of the present application
- FIG. 5 is a diagram illustrating an LC resonance voltage signal that changes according to a change in load resistance of the heat-generating body in one or more embodiments of the present application;
- FIG. 6 is a diagram illustrating a change in impedance corresponding to a change in frequency of a current mode class-D power amplifier including a parallel-structured LC resonant network in one or more embodiments of the present application;
- FIG. 7 is a diagram illustrating a current change characteristic corresponding to the change in frequency of the current mode class-D power amplifier including the parallel-structured LC resonant network in one or more embodiments of the present application;
- FIG. 8 is a diagram illustrating results obtained by simulating characteristics in a change in drain-source peak voltage applied when one transistor M 1 of a pair of transistor switches constituting the power amplifier is turned on/off corresponding to a change in switching frequency of the parallel-structured LC resonant network and a change in current amount of an inductor in one or more embodiments of the present application;
- FIG. 9 is a diagram for describing the operation of the current mode class-D power amplifier applied to one or more embodiments of the present application.
- FIGS. 10 and 11 are diagrams illustrating the maximum drain-source peak voltage and current applied during on/off operation of a pair of transistor switches M 1 and M 2 constituting the current mode class-D power amplifier;
- FIG. 12 is a diagram illustrating simulation results of drain-source peak voltage and current characteristics during operation of the current mode class-D power amplifier.
- FIG. 13 is a diagram illustrating simulation results of a change in peak voltage of an LC resonant network according to a change in load resistances (approximately 2 ⁇ , 1 ⁇ , and 0.5 ⁇ ) when the current mode class-D power amplifier operates at approximately 6.78 MHz in one or more embodiments of the present application.
- FIG. 2 is a block diagram conceptually illustrating an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette in accordance with one or more embodiments of the present application
- FIG. 3 is a circuit diagram of the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette in accordance with one or more embodiments of the present application
- FIG. 4 is a diagram illustrating an example in which a heat-generating body is included in one or more embodiments of the present application
- FIG. 5 is a diagram illustrating an LC resonance voltage signal that changes according to a change in load resistance of a heat-generating body in one or more embodiments of the present application.
- the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette is configured to include a power supply unit 10 , a driving unit 20 , and a power amplifier 30 .
- the power supply unit 10 is a component that supplies DC power, and for example, the power supply unit 10 may be configured to include a rechargeable DC battery.
- the power amplifier 30 may be configured to include a switch unit 32 , a parallel-structured LC resonant network 34 , and a choke inductor unit 36 .
- the switch unit 32 operates by receiving DC power from the power supply unit 10 and comprises a pair of transistor switches M 1 and M 2 having a differential structure.
- the pair of transistor switches M 1 and M 2 constituting the switch unit 32 may be metal oxide semiconductor field effect transistors (MOSFETs).
- MOSFETs metal oxide semiconductor field effect transistors
- the power amplifier 30 is a current mode class-D power amplifier, and the switch unit 32 constituting the power amplifier may be configured to induce resonance of the parallel-structured LC resonant network 34 to transfer power to a heat-generating body 40 .
- the parallel-structured LC resonant network 34 is connected to an output terminal of the switch unit 32 and comprises a resonant inductor L 1 electromagnetically inductively coupled to an inductor component of the heat-generating body 40 for heating the aerosol-forming article of the electronic cigarette, and a resonant capacitor C 1 connected in parallel to the resonant inductor L 1 .
- the parallel-structured LC resonant network 34 may be electrically connected to a drain of the first transistor switch M 1 and a drain of the second transistor switch M 2 .
- the choke inductor unit 36 may be configured to include a first choke inductor L 2 installed between the drain of the first transistor switch M 1 constituting the switch unit 32 and the power supply unit 10 and a second choke inductor L 3 installed between the drain of the two-transistor switch M 2 constituting the switch unit 32 and the power supply unit 10 .
- the driving unit 20 is a component that adjust an operating frequency of the switch unit 32 of the power amplifier 30 to control an amount of current of the resonant inductor L 1 electromagnetically inductively coupled with the inductor component of the heat-generating body, thereby adjusting a temperature of the heat-generating body.
- the driving unit 20 may be configured to limit the operating frequency of the switch unit 32 of the power amplifier 30 to an inductive susceptance frequency region lower than the resonance frequency of the parallel structure LC resonant network 34 , and has a characteristic that the amount of current of the resonant inductor L 1 is inversely proportional to the frequency in the inductive susceptance frequency region.
- FIG. 6 is a diagram illustrating a change in impedance corresponding to a change in frequency of a current mode class-D power amplifier including a parallel LC resonant network in one or more embodiments of the present application
- FIG. 7 is a diagram illustrating a current change characteristic corresponding to the change in frequency of the current mode class-D power amplifier including the parallel LC resonant network in one or more embodiments of the present application.
- a frequency f R is determined at a point where a value of a reactance X L component of the inductor and a value of a reactance X C component of the capacitor are the same, and the imaginary part of the admittance Y thereof is zero.
- the impedance Z of the resonant circuit of the parallel connection structure has a maximum value at the resonant frequency f R point as shown in FIG. 6 .
- the reactance value of each component is the same, and the admittance Y becomes minimum at the point where the total amount of reactance cancels out.
- FIG. 7 shows that the change in magnitude of current is a function of frequency in the frequency response curve of the parallel-connected resonant circuit. That is, this means that if the total current of the circuit showing the minimum value at the resonant frequency f R point approaches zero or changes to an infinite frequency at the resonant frequency f R , the magnitude of the current can be several times larger than that at the resonant frequency f R point.
- the electromagnetic induction heating apparatus for heating the aerosol-forming article since the purpose of the electromagnetic induction heating apparatus for heating the aerosol-forming article according to one or more embodiments of the present application is to heat a heat-generating body and efficiently control the temperature through an eddy current flowing in the inductor, it can be configured to use only the inductive susceptance (susceptibility) region having a curve inversely proportional to frequency.
- the drive unit 20 may be configured to operate the switch unit 32 of the power amplifier 30 at a frequency much lower than the resonant frequency f R in order to quickly increase the initial temperature of the heat-generating body, or configured to fix the operating frequency of the switch unit 32 in order to keep the temperature of the heating element constant after the heat-generating body reaches a specific temperature.
- FIG. 8 is a diagram illustrating results obtained by simulating characteristics in a change in drain-source peak voltage applied when one transistor M 1 of a pair of transistor switches constituting the power amplifier 30 is turned on/off and a change in current amount of an inductor in one or more embodiments of the present application.
- the operating frequency of the transistor switch at the reference resonance point is 6.78 MHz (f R ), and it is the result when the switch operating frequency is changed to 5.085 MHz (3/4f R ), which is 3/4 frequency of the reference resonance point, and 3.39 MHz (1/2f R ), which is 1/2 frequency, respectively, of the reference resonance point.
- the voltage of the voltage source VDC is 3.2 V and the load resistance is 1 ⁇ .
- the current induced in the inductor L 1 is an average of 2.04 A, but as the switching frequency is lowered to 3 ⁇ 4 frequency and 1 ⁇ 2 frequency of the reference resonance point, the amount of current induced in the inductor L 1 increases to 3.67 and 6.09, respectively.
- a change in amount of voltage and current according to a change in switch operating frequency has been simulated, but it is clear that this is an example and is not limited to specific implementations.
- the resonant frequency f R of the parallel LC resonant network 34 of the power amplifier 30 can be set in a very wide range by changing the values of the inductor L 1 and capacitor C 1 , and a usable inductive susceptance frequency region is also changed correspondingly.
- the driving unit 20 may be configured to estimate a change in temperature of the heat-generating body 40 by calculating a change in resistance value of the heat-generating body according to a voltage of the LC resonant network 34 , control the operation of the power amplifier 30 according to the estimated change in temperature, adjust output power of the power amplifier 30 including the parallel-structured LC resonant network 34 by varying the operating frequency of the switch unit 32 in response to the estimated change in temperature of the heat-generating body.
- the driving unit 20 may be configured to include a sensing circuit 22 , a main control unit (MCU) 24 , and a switch driver 26 .
- MCU main control unit
- the sensing circuit 22 senses the voltage of the parallel-structured LC resonant network 34 and transfers the voltage to the MCU 24 .
- the MCU 24 estimates the change in temperature of the heat-generating body 40 by calculating the change in resistance value of the heat-generating body 40 according to the voltage of the parallel-structured LC resonant network 34 sensed by the sensing circuit 22 , and generates a heat-generating body temperature control signal for controlling the temperature of the heat-generating body 40 according to the estimated change in temperature of the heat-generating body 40 and transfers the heat-generating body temperature control signal to the switch driver 26 .
- the switch driver 26 generates a switch driving signal for differentially driving the first transistor switch M 1 and the second transistor switch M 2 constituting the switch unit 32 according to the heat-generating body temperature control signal received from the MCU 24 and transfers the switch driving signal to gates of the first transistor switch M 1 and the second transistor switch M 2 .
- the driving unit 20 may be configured to calculate a change in the resistance value of the heat-generating body 40 according to the current used by the power amplifier 30 , control the operation of the power amplifier 30 according to the calculated change in resistance value, to actively control an amount of power transmitted to the heat-generating body by controlling the temperature of the heat-generating body using an impedance change characteristic that changes corresponding to a change in frequency of the parallel-structured LC resonant network 34 .
- the driving unit 20 may be configured to include the sensing circuit 22 , the MCU 24 , and the switch driver 26 .
- the sensing circuit 22 senses the current used by the power amplifier 30 and transfers the sensed current used by the power amplifier 30 to the MCU 24 .
- the MCU 24 calculates the change in the resistance value of the heat-generating body 40 according to the current used by the power amplifier 30 sensed by the sensing circuit 22 , generates a heat-generating body temperature control signal corresponding to the impedance change characteristic due to the change in frequency of the parallel-structured LC resonant network 34 in order to control the temperature of the heat-generating body 40 according to the calculated change in the resistance value of the heat-generating body 40 , and transfers the heat-generating body temperature control signal to the switch driver 26 .
- the switch driver 26 generates a switch driving signal for differentially driving the first transistor switch M 1 and the second transistor switch M 2 constituting the switch unit 32 according to the heat-generating body temperature control signal received from the MCU 24 , and transfers the switch driving signal to the gates of the first transistor switch M 1 and the second transistor switch M 2 .
- the pair of transistor switches M 1 and M 2 constituting the switch unit 32 can operate up to several GHz, but the pair of transistor switches M 1 and M 2 may be configured such that an operating frequency thereof is adjusted in the range of approximately 0.1 MHz to approximately 27.283 MHz in consideration of the purpose of the device and physical components.
- the driving unit 20 for implementing a method for sensing a temperature of the heat-generating body 40 and adjusting the temperature may be implemented in the form of a single silicon chip or a single package in order to minimize a volume of an electronic smoking apparatus.
- the drive unit 20 is not limited thereto, and may be configured by combining the components thereof into a single part.
- FIG. 9 is a diagram for describing an operation of a current mode class-D power amplifier applied to one or more embodiments of the present application
- FIGS. 10 and 11 are diagrams illustrating the maximum drain-source peak voltage and current applied during on/off operation of a pair of transistor switches M 1 and M 2 constituting the current mode class-D power amplifier.
- the electromagnetic induction heating apparatus for the purpose of heating the aerosol-forming article embodied in one or more embodiments of the present application includes the current mode class-D power amplifier.
- This power amplifier is configured with the pair of transistor switches M 1 and M 2 , a pair of choke inductors L 2 and L 3 , and a parallel-structured LC resonant network of L 1 and C 1 .
- the current mode class-D power amplifier is very advantageous in implementing the electronic smoking apparatus that needs to implement a small-sized apparatus and use limited power.
- drain-source peak voltages V DS1 and V DS2 applied to the pair of transistor switches M 1 and M 2 , respectively, of an amplifier operating in differential form can be interpreted by Equations 1 and 2.
- V DS ⁇ _ ⁇ peak ⁇ V DS [ Equation ⁇ 2 ]
- sq( ⁇ t) means a square wave including an infinite number of Fourier coefficients
- I D ( ⁇ t) has a maximum current value as expressed in Equation 5 due to the on/off operation of transistors M 1 and M 2 .
- Equations 2 and 5 The maximum drain-source peak voltage and current applied during on/off operation of the pair of transistor switches M 1 and M 2 defined by Equations 2 and 5 can be plotted as shown in FIGS. 7 and 8 , respectively.
- the current mode class-D power amplifier has a relatively low drain-to-peak voltage and current waveform characteristics in the form of the square wave limited to twice or less the I DC . Such characteristics may provide a wider range of options in selecting the use of transistors in forming a targeted apparatus and help to lower manufacturing cost.
- FIG. 12 is a diagram illustrating simulation results of the drain-source peak voltage and current characteristics during operation of the current mode class-D power amplifier.
- the operating frequency of the transistor switch is approximately 6.78 MHz
- the voltage of the voltage source VDC is approximately 3.2 V
- the load resistance is approximately 1 ⁇ .
- the maximum peak voltages V DS1 and V DS2 applied to the first and second transistor switches M 1 and M 2 , respectively, are approximately 10.1 V when VDC is approximately 3.2 V, which is very close to the value of approximately 10.05 V which can be obtained through Equation 2.
- the current waveform in the form of the square wave which is limited to twice or less the I DC , flows through the transistor.
- the measured values of the peak point A are approximately 9.583271 ⁇ s and approximately 10.10566 V and the measured values of the peak point B are approximately 9.658514 ⁇ s and approximately 10.11498 V.
- the power utilization factor of the current mode class-D power amplifier can be calculated through Equation 6.
- P max is the maximum power utilization factor
- P out is output power of the power amplifier.
- the output power of the power amplifier operating in a differential structure is as expressed in Equation 7, where V F1 and I F1 represent fundamental frequency components of the Fourier series of the voltage and the current, respectively.
- V F1 having a voltage characteristic in the form of a sine wave and I F1 having a characteristic in the form of a square wave can be defined as in Equation 8.
- V F ⁇ 1 ⁇ 2 ⁇ V DC
- I F ⁇ 1 4 ⁇ ⁇ I DC [ Equation ⁇ 8 ]
- Equation 7 is expressed as Equation 9 by Equation 8, and when applied to Equation 6 for the maximum power utilization factor, it is simplified to Equation 10.
- the maximum power utilization factor of the current mode class-D power amplifier is approximately 0.32, which shows a characteristic that is approximately 3.24 times higher than the power utilization factor of approximately 0.0981 of the class-E power amplifier, it provides a higher degree of convenience to a user in an application field that uses limited power (e-cigarettes in a narrow sense).
- the electromagnetic induction heating apparatus for heating the aerosol-forming article includes the driving unit 20 in which the MCU 24 , which is programmed to infer the change in temperature of the heat-generating body 40 by sensing input power of the power supply unit 10 , which is a DC voltage source, output power of the power amplifier 30 , and the voltage of the parallel-structured LC resonant network 34 , determines whether or not the power amplifier 30 operates, This means that even if the heat-generating body 40 is in a non-contact state with the electromagnetic induction heating apparatus for heating the aerosol-forming article according to one or more embodiments of the present application, whether or not the power amplifier 30 operates can be determined by inferring the change in temperature. As described in more detail below, the current mode class-D power amplifier can actively determine whether or not to operate in response to the change in temperature of the heat-generating body 40 including a certain level of load resistance of interest to the user.
- the inductance of the inductor L 1 and capacitance of the capacitor C 1 used in the parallel resonant network of the current mode class-D power amplifier may be selected by the operating frequency and the load resistance value.
- Q LC in Equation 11 below is a quality factor of the resonant circuit and is a value selectable by the user.
- the inductance of the inductor L 1 and the capacitance of capacitor C 1 can be selected according to Equation 12 by a specific load resistance value R L.
- the power amplifier 30 which includes the parallel-structured LC resonant network 34 having the inductance of the inductor L 1 and the capacitance of the capacitor C 1 selected for the purpose of heating the heat-generating body 40 having a specific load resistance value R L , needs to sense the temperature of the heat-generating body 40 to determine the operating range.
- an apparatus for temperature sensing e.g., a negative temperature coefficient (NTC) thermistor or a positive temperature coefficient (PTC) and a thermocouple device, i.e., a thermocouple, etc.
- a method of estimating an apparent resistance value by sensing a current used by the power amplifier 30 and a change amount thereof may also be used in order to sense an increase and change in the temperature of the heat-generating body.
- an eddy current generated by an initial operation of the power amplifier 30 will continuously increase the temperature of the heat-generating body 40 .
- the resistance value of the heat-generating body 40 which is typically implemented with a metal component, increases as the temperature thereof rises, and the resistance value increases up to the temperature (Curie temperature or Curie point) at which electromagnetic induction is no longer caused by the eddy current.
- the current used by the power amplifier 30 decreases in response to the increase in the resistance value generated at this time, and the MCU 24 may calculate the change amount thereof through the sensing circuit 22 to calculate the apparent resistance value of the heat-generating body 40 .
- Another example for sensing the temperature of the heat-generating body configured in a non-contact form with the induction heating apparatus is sensing a change in temperature through the change in the resistance value of the heat-generating body 40 by sensing a voltage V LC of the parallel-structured LC resonant network 34 .
- the voltage V LC of the parallel-structured LC resonant network 34 of the current mode class-D power amplifier operating at a fixed frequency shows a constant peak voltage characteristic corresponding to a specific load resistance value R L. This constant peak voltage characteristic is only dependent on the change in resistance value of the heat-generating body 40 if the capacity and operating frequency of the parallel-structured LC resonant network 34 are fixed.
- the resistance value increases as the temperature of the heat-generating body 40 and V LC decreases as the resistance value increases.
- the change amount of V LC is transferred to the MCU 24 , which is programmed, through the sensing circuit 22 , and it is possible to determine, by calculating the change amount of V LC , whether or not the switch driver 26 operates in order to respond to the change in temperature of the heat-generating body 40 .
- a configuration may be made such that the sensing circuit 22 senses the voltage V LC of the parallel-structured LC resonant network 34 and transfers the voltage V LC to the MCU 24 , the MCU 24 estimates the change in temperature of the heat-generating body 40 by calculating the change in resistance value of the heat-generating body 40 according to the voltage V LC of the parallel-structured LC resonant network 34 sensed by the sensing circuit 22 and generates a heat-generating body temperature control signal for controlling the temperature of the heat-generating body 40 and transmits the heat-generating body temperature control signal to the switch driver 26 , and the switch driver 26 generates a switch driving signal for differentially driving the pair of transistor switches M 1 and M 2 constituting the switch unit 32 according to the heat-generating body temperature control signal transferred from the MCU 24 .
- FIG. 13 is a diagram illustrating simulation results of a change in peak voltage of a parallel-structured LC resonant network according to a change in load resistances (approximately 2 ⁇ , 1 ⁇ , and 0.5 ⁇ , respectively) when the current mode class-D power amplifier operates at approximately 6.78 MHz in one or more embodiments of the present application.
- the measured values of the peak point C are approximately 5.21534 ⁇ s and approximately 11.15368 V
- the measured values of the peak point D are approximately 5.217782 ⁇ s and approximately 10.11192 V
- the measured values of the peak point E are approximately 5.228352 ⁇ s and approximately 9.385039 V.
- the MCU 24 may stop the operation of the power amplifier 30 in order to lower the temperature of the heat-generating body 40 .
- V LC is detected in the form of rising again, and at this time, the MCU 24 may operate the power amplifier again to maintain the temperature of the heat-generating body constant.
- the V LC may be connected to the sensing circuit 22 through a normal peak detector circuit using a diode or operation amplifier among peak detectors.
- a combination of the apparent resistance value estimation and LC resonance voltage sensing described above may also be used in order to actively sense the temperature of the heat-generating body 40 and determine whether or not the power amplifier 30 operates in response thereto.
- the performance of such an operation can be selectively controlled by the MCU 24 constituting the driving unit 20 , and can immediately control the operation time and time point of the power amplifier 30 with respect to the change in temperature of the heat-generating body 40 that occurs when a user repeats an act of inhaling an electronic smoking article using the heat-generating body 40 so that the heat-generating body 40 for forming aerosol always maintains an optimal heating temperature.
- one or more embodiments of the present application provide an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette, which can maximize a power utilization factor in a process of heating the aerosol-forming article of the electronic cigarette using a heat-generating body, can reduce the implementation and manufacturing difficulty of the apparatus, and can adaptively control a heating temperature of the heat-generating body, and a driving method thereof.
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Abstract
Description
- This application claims priority to Korean Patent Application No. 10-2022-0137553 filed on Oct. 24, 2022 and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which are incorporated by reference in their entirety.
- One or more embodiments of the present disclosure relate to an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette using a heat-generating body and a driving method thereof. More specifically, one or more embodiments of the present disclosure relate to an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette, which can maximize a power utilization factor in a process of heating the aerosol-forming article of the electronic cigarette using the heat-generating body, can reduce the implementation and manufacturing difficulty of the apparatus, and can adaptively control a heating temperature of the heat-generating body and a driving method thereof.
- Generally, electronic apparatuses using aerosol-forming tobacco-containing articles to replace cigarettes are known.
- In one prior art for aerosol formation, there is a resistive heat generation induction method of inducing resistive heat generation using a heatable metal heat-generating body and heating the aerosol-forming article to a temperature at which volatile components can be released by directly contacting the aerosol-forming article with the metal heat-generating body. According to the resistive heat generation induction method, the metal heat-generating body may be implemented to have various shapes by using metal objects such as a heating blade, a heating spear, and a heating can.
- In another prior art for aerosol formation, there is an electromagnetic inductive heating method using heat generation characteristics corresponding to power loss by generating eddy currents in order to increase the temperature of the heatable metal heat-generating body. According to this electromagnetic inductive heating method, an AC magnetic field is generated in an LC-type resonant network including an inductor to raise the temperature of the metal heat-generating body, and the aerosol-forming article in contact with the metal heat-generating body is heated to the temperature at which volatile components are released. In this case, the metal heat-generating body may be implemented to have various shapes by using a metal component, similar to the resistive heat-generating body.
- According to the resistive heat generation induction method, the heat-generating body should physically contact the electronic apparatus; whereas, according to the electromagnetic inductive heating method, the heat-generating body can be heated when the heat-generating body is physically in contact with or not in contact with the electronic apparatus.
- The electromagnetic inductive heating method as described above can quickly raise the heat-generating body to a target temperature compared to the resistive heat generation induction method, and can provide users with high usability when using limited power through a relatively high power utilization factor.
- Hereinafter, conventional electromagnetic inductive heating technology will be described by citing Korean unexamined patent application publication No. 10-2020-0003938, which discloses an electromagnetic induction heating technology.
-
FIG. 1 is a diagram illustrating a class-E power amplifier structure published in Korean unexamined patent application publication No. 10-2020-0003938. - Referring to
FIG. 1 , Korean unexamined patent application publication No. 10-2020-0003938 uses an amplifier power with class-E structure for the rapidity of heating and the formation of a small-sized apparatus. Since the class-E power amplifier includes an LC load network that includes a series connection form of an inductor and capacitor and operates with only a single switch, the class-E power amplifier is suitable for the formation of a small-sized apparatus. In addition, since the class-E power amplifier is a power amplifier that operates in a switch mode, it is suitable for electromagnetic induction heating compared to other linear mode power amplifiers and is thus effective in forming aerosol by rapidly heating a heat-generating body. - However, the class-E power amplifier has a very high drain-to-source peak voltage across the switch (
reference numeral 1320 inFIG. 1 ) due to the structure and operation characteristics thereof, and thus a switch element with a high breakdown voltage is necessarily required. This will act as a very large barrier to restrictions on the use of parts and increase in unit cost in implementing the device. - In addition, since the class-E power amplifier has peak-shaped current waveform characteristics along with the high drain-source peak voltage, it has a disadvantage of lowering a power utilization factor of the power amplifier. As detailed in a paper (“Idealized Operation of the Class E Tuned Power Amplifier”, F. H. Raab) published in IEEE Transactions on Circuits and Systems, December 1977, vol. CAS-24, NO.:12, pages 725-735, the power utilization factor of the class-E power amplifier is very low at approximately 0.0981, which can be attributed to numerical values of a high peak voltage of approximately 3.56 and high peak current of approximately 2.86 applied to the switch.
- As described above, the electromagnetic induction heating apparatus using the class-E power amplifier requires a user to repeat a charging process, especially in an application field (e-cigarette in a narrow sense) that uses a limited voltage and current source (battery or capacitor).
- In addition, as described above, since the electromagnetic induction heating apparatus using the class-E power amplifier requires a switch having) a breakdown voltage several times higher than (normally approximately 3.56 times, as high as approximately 7 times) the voltage source used to ensure stable operation of the apparatus, the difficulty of implementing the apparatus is very high.
- (PTL 1) Korean unexamined patent application publication No. 10-2020-0003938 (published date: Jan. 10, 2020, Title: Induction heating device for heating aerosol-forming base material)
- One or more embodiments of the present disclosure provide an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette, which can maximize a power utilization factor in a process of heating the aerosol-forming article of the electronic cigarette using a heat-generating body, can reduce the implementation and manufacturing difficulty of the apparatus, and can adaptively control a heating temperature of the heat-generating body and a driving method thereof.
- In accordance with one or more embodiments of the present application, an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette includes a power supply unit configured to supply DC power; a power amplifier including a switch unit comprising a pair of transistor switches having a differential structure and operating by receiving the DC power from the power supply unit and a parallel-structured LC resonant network comprising a resonant inductor connected to an output terminal of the switch unit and electromagnetically inductively coupled with an inductor component of a heat-generating body for heating the aerosol-forming article of the electronic cigarette and a resonant capacitor connected in parallel to the resonant inductor; and a driving unit configured to adjust a temperature of the heat-generating body by adjusting an operating frequency of the switch unit of the power amplifier to control an amount of current of the resonant inductor electromagnetically inductively coupled with the inductor component of the heat-generating body.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may be configured to limit the operating frequency of the switch unit of the power amplifier to an inductive susceptance frequency region lower than a resonance frequency of the parallel-structured LC resonant network.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the amount of current of the resonant inductor is inversely proportional to frequency in the inductive susceptance frequency region.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the power amplifier may be a current mode class-D power amplifier, and the switch unit constituting the power amplifier may be configured to induce resonance of the parallel-structured LC resonant network to transfer power to the heat-generating body.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the power amplifier may further include a first choke inductor, installed between a drain of a first transistor switch constituting the switch unit and the power supply unit, and a second choke inductor, installed between a drain of a second transistor switch constituting the switch unit and the power supply unit. The parallel-structured LC resonant network may be connected to the drain of the first transistor switch and the drain of the second transistor switch.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may be configured to estimate a change in temperature of the heat-generating body by calculating a change in resistance value of the heat-generating body according to a voltage of the parallel-structured LC resonant network, and control the operation of the power amplifier according to the estimated change in temperature of the heat-generating body.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may be configured to adjust output power of the power amplifier including the parallel-structured LC resonant network by varying the operating frequency of the switch unit in response to the estimated change in temperature of the heat-generating body.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may include a sensing circuit configured to sense a voltage of the parallel-structured LC resonant network, an MCU configured to estimate a change in temperature of the heat-generating body, by calculating a change in resistance value of the heat-generating body according to the voltage of the parallel-structured LC resonant network sensed by the sensing circuit, and generate a heat-generating body temperature control signal for controlling a temperature of the heat-generating body according to the estimated change in temperature of the heat-generating body, and a switch driver configured to generate a switch driving signal for differentially driving the pair of transistor switches constituting the switch unit according to the heat-generating body temperature control signal received from the MCU.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may be configured to calculate a change in resistance value of the heat-generating body according to a current used by the power amplifier and control the operation of the power amplifier according to the calculated change in resistance value of the heat-generating body.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may be configured to actively control an amount of power transferred to the heat-generating body by controlling the temperature of the heat-generating body using an impedance change characteristic that changes according to a change in frequency of the parallel-structured LC resonant network.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the driving unit may include a sensing circuit configured to sense a current used by the power amplifier, an MCU configured to calculate a change in resistance value of the heat-generating body according to the current used by the power amplifier sensed by the sensing circuit and generate a heat-generating body temperature control signal corresponding to an impedance change characteristic due to a change in frequency of the parallel-structured LC resonant network, in order to control a temperature of the heat-generating body according to the calculated change in resistance value of the heat-generating body, and a switch driver configured to generate a switch driving signal for differentially driving the pair of transistor switches constituting the switch unit according to the heat-generating body temperature control signal received from the MCU.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, an operating frequency of the pair of transistor switches constituting the switch unit may be approximately 0.1 MHz to approximately 27.283 MHz.
- In the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette, the power supply unit may include a rechargeable DC battery.
- Exemplary embodiments can be understood in more detail from the following description taken in conjunction with the accompanying drawings, in which:
-
FIG. 1 is a diagram illustrating the structure of a class-E power amplifier published in the prior art; -
FIG. 2 is a block diagram conceptually illustrating an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette in accordance with one or more embodiments of the present application; -
FIG. 3 is a circuit diagram of the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette in accordance with one or more embodiments of the present application; -
FIG. 4 is a diagram illustrating an example in which a heat-generating body is included in one or more embodiments of the present application; -
FIG. 5 is a diagram illustrating an LC resonance voltage signal that changes according to a change in load resistance of the heat-generating body in one or more embodiments of the present application; -
FIG. 6 is a diagram illustrating a change in impedance corresponding to a change in frequency of a current mode class-D power amplifier including a parallel-structured LC resonant network in one or more embodiments of the present application; -
FIG. 7 is a diagram illustrating a current change characteristic corresponding to the change in frequency of the current mode class-D power amplifier including the parallel-structured LC resonant network in one or more embodiments of the present application; -
FIG. 8 is a diagram illustrating results obtained by simulating characteristics in a change in drain-source peak voltage applied when one transistor M1 of a pair of transistor switches constituting the power amplifier is turned on/off corresponding to a change in switching frequency of the parallel-structured LC resonant network and a change in current amount of an inductor in one or more embodiments of the present application; -
FIG. 9 is a diagram for describing the operation of the current mode class-D power amplifier applied to one or more embodiments of the present application; -
FIGS. 10 and 11 are diagrams illustrating the maximum drain-source peak voltage and current applied during on/off operation of a pair of transistor switches M1 and M2 constituting the current mode class-D power amplifier; -
FIG. 12 is a diagram illustrating simulation results of drain-source peak voltage and current characteristics during operation of the current mode class-D power amplifier; and -
FIG. 13 is a diagram illustrating simulation results of a change in peak voltage of an LC resonant network according to a change in load resistances (approximately 2Ω, 1Ω, and 0.5Ω) when the current mode class-D power amplifier operates at approximately 6.78 MHz in one or more embodiments of the present application. - Specific structural or functional descriptions of embodiments according to the concept of the present application disclosed in this specification are only illustrated for the purpose of explaining the embodiments according to the concept of the present application, and the embodiments according to the concept of the present application may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.
- Various modifications may be made to the embodiments according to the concept of the present application and the embodiments can have various forms, and thus the embodiments are illustrated in the drawings and described in detail in this specification. However, this is not intended to limit the embodiments according to the concept of the present application to specific disclosure forms, and includes all modifications, equivalents, or substitutes included in the spirit and technical scope of the present application.
- Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the prior art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application.
- Hereinafter, one or more embodiments of the present application will be described in detail with reference to the accompanying drawings.
-
FIG. 2 is a block diagram conceptually illustrating an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette in accordance with one or more embodiments of the present application,FIG. 3 is a circuit diagram of the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette in accordance with one or more embodiments of the present application,FIG. 4 is a diagram illustrating an example in which a heat-generating body is included in one or more embodiments of the present application, andFIG. 5 is a diagram illustrating an LC resonance voltage signal that changes according to a change in load resistance of a heat-generating body in one or more embodiments of the present application. - Referring to
FIGS. 2 to 5 , the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette according to one or more embodiments of the present application is configured to include apower supply unit 10, a drivingunit 20, and apower amplifier 30. - The
power supply unit 10 is a component that supplies DC power, and for example, thepower supply unit 10 may be configured to include a rechargeable DC battery. - The
power amplifier 30 may be configured to include aswitch unit 32, a parallel-structured LCresonant network 34, and achoke inductor unit 36. - The
switch unit 32 operates by receiving DC power from thepower supply unit 10 and comprises a pair of transistor switches M1 and M2 having a differential structure. - For example, the pair of transistor switches M1 and M2 constituting the
switch unit 32 may be metal oxide semiconductor field effect transistors (MOSFETs). - In addition, the
power amplifier 30 is a current mode class-D power amplifier, and theswitch unit 32 constituting the power amplifier may be configured to induce resonance of the parallel-structured LCresonant network 34 to transfer power to a heat-generatingbody 40. - The parallel-structured LC
resonant network 34 is connected to an output terminal of theswitch unit 32 and comprises a resonant inductor L1 electromagnetically inductively coupled to an inductor component of the heat-generatingbody 40 for heating the aerosol-forming article of the electronic cigarette, and a resonant capacitor C1 connected in parallel to the resonant inductor L1. - For example, when the
switch unit 32 comprises two MOSFET elements coupled in a differential operation structure, the parallel-structured LCresonant network 34 may be electrically connected to a drain of the first transistor switch M1 and a drain of the second transistor switch M2. - The
choke inductor unit 36 may be configured to include a first choke inductor L2 installed between the drain of the first transistor switch M1 constituting theswitch unit 32 and thepower supply unit 10 and a second choke inductor L3 installed between the drain of the two-transistor switch M2 constituting theswitch unit 32 and thepower supply unit 10. - The driving
unit 20 is a component that adjust an operating frequency of theswitch unit 32 of thepower amplifier 30 to control an amount of current of the resonant inductor L1 electromagnetically inductively coupled with the inductor component of the heat-generating body, thereby adjusting a temperature of the heat-generating body. - For example, the driving
unit 20 may be configured to limit the operating frequency of theswitch unit 32 of thepower amplifier 30 to an inductive susceptance frequency region lower than the resonance frequency of the parallel structure LCresonant network 34, and has a characteristic that the amount of current of the resonant inductor L1 is inversely proportional to the frequency in the inductive susceptance frequency region. - This configuration will be described in detail with further reference to
FIGS. 6 to 8 as follows. -
FIG. 6 is a diagram illustrating a change in impedance corresponding to a change in frequency of a current mode class-D power amplifier including a parallel LC resonant network in one or more embodiments of the present application, andFIG. 7 is a diagram illustrating a current change characteristic corresponding to the change in frequency of the current mode class-D power amplifier including the parallel LC resonant network in one or more embodiments of the present application. - Referring further to
FIGS. 6 and 7 , it is clear that, in the case of a resonant circuit comprising an inductor L and a capacitor C, in both series and parallel connection structure resonant circuits, a frequency fR is determined at a point where a value of a reactance XL component of the inductor and a value of a reactance XC component of the capacitor are the same, and the imaginary part of the admittance Y thereof is zero. - On the other hand, unlike the resonant circuit of the series connection structure, the impedance Z of the resonant circuit of the parallel connection structure has a maximum value at the resonant frequency fR point as shown in
FIG. 6 . As a result, the reactance value of each component is the same, and the admittance Y becomes minimum at the point where the total amount of reactance cancels out. - Through the impedance characteristic curve of the parallel-connected resonant circuit, it can be seen that the total current flowing through the circuit at the resonant frequency fR is minimum because the inductor and capacitor currents are equal in amount and in opposite phase.
-
FIG. 7 shows that the change in magnitude of current is a function of frequency in the frequency response curve of the parallel-connected resonant circuit. That is, this means that if the total current of the circuit showing the minimum value at the resonant frequency fR point approaches zero or changes to an infinite frequency at the resonant frequency fR, the magnitude of the current can be several times larger than that at the resonant frequency fR point. - Referring back to
FIG. 7 , since the purpose of the electromagnetic induction heating apparatus for heating the aerosol-forming article according to one or more embodiments of the present application is to heat a heat-generating body and efficiently control the temperature through an eddy current flowing in the inductor, it can be configured to use only the inductive susceptance (susceptibility) region having a curve inversely proportional to frequency. - In one or more embodiments of the present application, the
drive unit 20 may be configured to operate theswitch unit 32 of thepower amplifier 30 at a frequency much lower than the resonant frequency fR in order to quickly increase the initial temperature of the heat-generating body, or configured to fix the operating frequency of theswitch unit 32 in order to keep the temperature of the heating element constant after the heat-generating body reaches a specific temperature. -
FIG. 8 is a diagram illustrating results obtained by simulating characteristics in a change in drain-source peak voltage applied when one transistor M1 of a pair of transistor switches constituting thepower amplifier 30 is turned on/off and a change in current amount of an inductor in one or more embodiments of the present application. - In the simulation illustrated in
FIG. 8 , the operating frequency of the transistor switch at the reference resonance point is 6.78 MHz (fR), and it is the result when the switch operating frequency is changed to 5.085 MHz (3/4fR), which is 3/4 frequency of the reference resonance point, and 3.39 MHz (1/2fR), which is 1/2 frequency, respectively, of the reference resonance point. In this case, the voltage of the voltage source VDC is 3.2 V and the load resistance is 1 Ω. - It can be seen that when the resonant frequency fR and the switching frequency of the
power amplifier 30 are the same, the current induced in the inductor L1 is an average of 2.04 A, but as the switching frequency is lowered to ¾ frequency and ½ frequency of the reference resonance point, the amount of current induced in the inductor L1 increases to 3.67 and 6.09, respectively. In the above, as one embodiment, a change in amount of voltage and current according to a change in switch operating frequency has been simulated, but it is clear that this is an example and is not limited to specific implementations. This is because, for example, the resonant frequency fR of the parallel LCresonant network 34 of thepower amplifier 30 can be set in a very wide range by changing the values of the inductor L1 and capacitor C1, and a usable inductive susceptance frequency region is also changed correspondingly. - For example, the driving
unit 20 may be configured to estimate a change in temperature of the heat-generatingbody 40 by calculating a change in resistance value of the heat-generating body according to a voltage of the LCresonant network 34, control the operation of thepower amplifier 30 according to the estimated change in temperature, adjust output power of thepower amplifier 30 including the parallel-structured LCresonant network 34 by varying the operating frequency of theswitch unit 32 in response to the estimated change in temperature of the heat-generating body. - In one or more embodiments, the driving
unit 20 may be configured to include asensing circuit 22, a main control unit (MCU) 24, and aswitch driver 26. - The
sensing circuit 22 senses the voltage of the parallel-structured LCresonant network 34 and transfers the voltage to theMCU 24. - The
MCU 24 estimates the change in temperature of the heat-generatingbody 40 by calculating the change in resistance value of the heat-generatingbody 40 according to the voltage of the parallel-structured LCresonant network 34 sensed by thesensing circuit 22, and generates a heat-generating body temperature control signal for controlling the temperature of the heat-generatingbody 40 according to the estimated change in temperature of the heat-generatingbody 40 and transfers the heat-generating body temperature control signal to theswitch driver 26. Theswitch driver 26 generates a switch driving signal for differentially driving the first transistor switch M1 and the second transistor switch M2 constituting theswitch unit 32 according to the heat-generating body temperature control signal received from theMCU 24 and transfers the switch driving signal to gates of the first transistor switch M1 and the second transistor switch M2. - In addition, for example, the driving
unit 20 may be configured to calculate a change in the resistance value of the heat-generatingbody 40 according to the current used by thepower amplifier 30, control the operation of thepower amplifier 30 according to the calculated change in resistance value, to actively control an amount of power transmitted to the heat-generating body by controlling the temperature of the heat-generating body using an impedance change characteristic that changes corresponding to a change in frequency of the parallel-structured LCresonant network 34. - In one or more embodiments, the driving
unit 20 may be configured to include thesensing circuit 22, theMCU 24, and theswitch driver 26. - The
sensing circuit 22 senses the current used by thepower amplifier 30 and transfers the sensed current used by thepower amplifier 30 to theMCU 24. - The
MCU 24 calculates the change in the resistance value of the heat-generatingbody 40 according to the current used by thepower amplifier 30 sensed by thesensing circuit 22, generates a heat-generating body temperature control signal corresponding to the impedance change characteristic due to the change in frequency of the parallel-structured LCresonant network 34 in order to control the temperature of the heat-generatingbody 40 according to the calculated change in the resistance value of the heat-generatingbody 40, and transfers the heat-generating body temperature control signal to theswitch driver 26. - The
switch driver 26 generates a switch driving signal for differentially driving the first transistor switch M1 and the second transistor switch M2 constituting theswitch unit 32 according to the heat-generating body temperature control signal received from theMCU 24, and transfers the switch driving signal to the gates of the first transistor switch M1 and the second transistor switch M2. - For example, the pair of transistor switches M1 and M2 constituting the
switch unit 32 can operate up to several GHz, but the pair of transistor switches M1 and M2 may be configured such that an operating frequency thereof is adjusted in the range of approximately 0.1 MHz to approximately 27.283 MHz in consideration of the purpose of the device and physical components. - For example, the driving
unit 20 for implementing a method for sensing a temperature of the heat-generatingbody 40 and adjusting the temperature may be implemented in the form of a single silicon chip or a single package in order to minimize a volume of an electronic smoking apparatus. However, thedrive unit 20 is not limited thereto, and may be configured by combining the components thereof into a single part. - Hereinafter, one or more embodiments of the present application will be described more specifically and exemplarily by further referring to
FIGS. 9 to 13 . -
FIG. 9 is a diagram for describing an operation of a current mode class-D power amplifier applied to one or more embodiments of the present application, andFIGS. 10 and 11 are diagrams illustrating the maximum drain-source peak voltage and current applied during on/off operation of a pair of transistor switches M1 and M2 constituting the current mode class-D power amplifier. - Referring further to
FIGS. 9 to 11 , the electromagnetic induction heating apparatus for the purpose of heating the aerosol-forming article embodied in one or more embodiments of the present application includes the current mode class-D power amplifier. This power amplifier is configured with the pair of transistor switches M1 and M2, a pair of choke inductors L2 and L3, and a parallel-structured LC resonant network of L1 and C1. - The current mode class-D power amplifier is very advantageous in implementing the electronic smoking apparatus that needs to implement a small-sized apparatus and use limited power.
- As illustrated in
FIG. 9 , drain-source peak voltages VDS1 and VDS2 applied to the pair of transistor switches M1 and M2, respectively, of an amplifier operating in differential form can be interpreted byEquations -
- In this case, due to the structural characteristics of the power amplifier in which the parallel-structured LC resonant network and the load are connected in parallel, harmonic components are short-circuited and only the fundamental resonant frequency is applied to the load, and thus the current applied to the transistor has a square wave form, and drain peak currents ID1 and ID2 at this time can be interpreted by
Equation 3, Equation 4, and Equation 5 below. -
- Referring to Equation 4, sq(ωt) means a square wave including an infinite number of Fourier coefficients, and ID(ωt) has a maximum current value as expressed in Equation 5 due to the on/off operation of transistors M1 and M2.
- The maximum drain-source peak voltage and current applied during on/off operation of the pair of transistor switches M1 and M2 defined by
Equations 2 and 5 can be plotted as shown inFIGS. 7 and 8 , respectively. - As described earlier, compared to the high drain-source peak voltage applied to the transistor switch (approximately 3.56 times that of the voltage source) and the current waveform characteristics in the form of a peak, which are characteristics of the class-E structure power amplifier of the prior art, the current mode class-D power amplifier has a relatively low drain-to-peak voltage and current waveform characteristics in the form of the square wave limited to twice or less the IDC. Such characteristics may provide a wider range of options in selecting the use of transistors in forming a targeted apparatus and help to lower manufacturing cost.
-
FIG. 12 is a diagram illustrating simulation results of the drain-source peak voltage and current characteristics during operation of the current mode class-D power amplifier. - In the simulation illustrated in
FIG. 12 , the operating frequency of the transistor switch is approximately 6.78 MHz, the voltage of the voltage source VDC is approximately 3.2 V, and the load resistance is approximately 1Ω. - Through this simulation result, it can be seen that the maximum peak voltages VDS1 and VDS2 applied to the first and second transistor switches M1 and M2, respectively, are approximately 10.1 V when VDC is approximately 3.2 V, which is very close to the value of approximately 10.05 V which can be obtained through
Equation 2. In addition, it can be seen that the current waveform in the form of the square wave, which is limited to twice or less the IDC, flows through the transistor. InFIG. 12 , the measured values of the peak point A are approximately 9.583271 μs and approximately 10.10566 V and the measured values of the peak point B are approximately 9.658514 μs and approximately 10.11498 V. - Through the equations and simulation verification described above, the power utilization factor of the current mode class-D power amplifier can be calculated through Equation 6.
-
- In this case, Pmax is the maximum power utilization factor, and Pout is output power of the power amplifier. The output power of the power amplifier operating in a differential structure is as expressed in Equation 7, where VF1 and IF1 represent fundamental frequency components of the Fourier series of the voltage and the current, respectively.
-
- As shown in the simulation results, VF1 having a voltage characteristic in the form of a sine wave and IF1 having a characteristic in the form of a square wave can be defined as in Equation 8.
-
- As a result, Equation 7 is expressed as Equation 9 by Equation 8, and when applied to Equation 6 for the maximum power utilization factor, it is simplified to
Equation 10. -
- That is, since the maximum power utilization factor of the current mode class-D power amplifier is approximately 0.32, which shows a characteristic that is approximately 3.24 times higher than the power utilization factor of approximately 0.0981 of the class-E power amplifier, it provides a higher degree of convenience to a user in an application field that uses limited power (e-cigarettes in a narrow sense).
- Meanwhile, as described earlier, the electromagnetic induction heating apparatus for heating the aerosol-forming article according to one or more embodiments of the present application includes the driving
unit 20 in which theMCU 24, which is programmed to infer the change in temperature of the heat-generatingbody 40 by sensing input power of thepower supply unit 10, which is a DC voltage source, output power of thepower amplifier 30, and the voltage of the parallel-structured LCresonant network 34, determines whether or not thepower amplifier 30 operates, This means that even if the heat-generatingbody 40 is in a non-contact state with the electromagnetic induction heating apparatus for heating the aerosol-forming article according to one or more embodiments of the present application, whether or not thepower amplifier 30 operates can be determined by inferring the change in temperature. As described in more detail below, the current mode class-D power amplifier can actively determine whether or not to operate in response to the change in temperature of the heat-generatingbody 40 including a certain level of load resistance of interest to the user. - The inductance of the inductor L1 and capacitance of the capacitor C1 used in the parallel resonant network of the current mode class-D power amplifier may be selected by the operating frequency and the load resistance value. Q LC in Equation 11 below is a quality factor of the resonant circuit and is a value selectable by the user. In a state where a transistor switching frequency is fixed to one of the operating frequencies used in one or more embodiments of the present application, the inductance of the inductor L1 and the capacitance of capacitor C1 can be selected according to Equation 12 by a specific load resistance value R L.
-
- However, in the case of the current mode class-D power amplifier, since the parallel-structured LC
resonant network 34 is located in parallel with a load resistor, it is necessary to consider the CDS1 and CDS2 (drain-source capacitance) components of the transistor switches M1 and M2 when selecting the capacitance of the resonant capacitor C1, which can be reflected by an experimental value. - The
power amplifier 30, which includes the parallel-structured LCresonant network 34 having the inductance of the inductor L1 and the capacitance of the capacitor C1 selected for the purpose of heating the heat-generatingbody 40 having a specific load resistance value RL, needs to sense the temperature of the heat-generatingbody 40 to determine the operating range. In the case of an apparatus manufactured with a heat-generating body in contact with an induction heating apparatus, change in temperature can be intuitively sensed using an apparatus for temperature sensing, e.g., a negative temperature coefficient (NTC) thermistor or a positive temperature coefficient (PTC) and a thermocouple device, i.e., a thermocouple, etc. - However, in the case of a heat-generating body configured in a non-contact form with the induction heating apparatus, since it is not possible to use the contact type temperature sensing apparatus described above, a method of estimating an apparent resistance value by sensing a current used by the
power amplifier 30 and a change amount thereof may also be used in order to sense an increase and change in the temperature of the heat-generating body. For example, an eddy current generated by an initial operation of thepower amplifier 30 will continuously increase the temperature of the heat-generatingbody 40. The resistance value of the heat-generatingbody 40, which is typically implemented with a metal component, increases as the temperature thereof rises, and the resistance value increases up to the temperature (Curie temperature or Curie point) at which electromagnetic induction is no longer caused by the eddy current. The current used by thepower amplifier 30 decreases in response to the increase in the resistance value generated at this time, and theMCU 24 may calculate the change amount thereof through thesensing circuit 22 to calculate the apparent resistance value of the heat-generatingbody 40. - Another example for sensing the temperature of the heat-generating body configured in a non-contact form with the induction heating apparatus is sensing a change in temperature through the change in the resistance value of the heat-generating
body 40 by sensing a voltage VLC of the parallel-structured LCresonant network 34. As shown inFIG. 5 , the voltage VLC of the parallel-structured LCresonant network 34 of the current mode class-D power amplifier operating at a fixed frequency shows a constant peak voltage characteristic corresponding to a specific load resistance value R L. This constant peak voltage characteristic is only dependent on the change in resistance value of the heat-generatingbody 40 if the capacity and operating frequency of the parallel-structured LCresonant network 34 are fixed. Referring to the temperature change characteristics of the metal component heat-generating body described above, it is clear that, compared to the voltage VLC of the parallel-structured LCresonant network 34 during initial operation of thepower amplifier 30, the resistance value increases as the temperature of the heat-generatingbody 40 and VLC decreases as the resistance value increases. Similarly, the change amount of VLC is transferred to theMCU 24, which is programmed, through thesensing circuit 22, and it is possible to determine, by calculating the change amount of VLC, whether or not theswitch driver 26 operates in order to respond to the change in temperature of the heat-generatingbody 40. That is, a configuration may be made such that thesensing circuit 22 senses the voltage VLC of the parallel-structured LCresonant network 34 and transfers the voltage VLC to theMCU 24, theMCU 24 estimates the change in temperature of the heat-generatingbody 40 by calculating the change in resistance value of the heat-generatingbody 40 according to the voltage VLC of the parallel-structured LCresonant network 34 sensed by thesensing circuit 22 and generates a heat-generating body temperature control signal for controlling the temperature of the heat-generatingbody 40 and transmits the heat-generating body temperature control signal to theswitch driver 26, and theswitch driver 26 generates a switch driving signal for differentially driving the pair of transistor switches M1 and M2 constituting theswitch unit 32 according to the heat-generating body temperature control signal transferred from theMCU 24. -
FIG. 13 is a diagram illustrating simulation results of a change in peak voltage of a parallel-structured LC resonant network according to a change in load resistances (approximately 2Ω, 1Ω, and 0.5Ω, respectively) when the current mode class-D power amplifier operates at approximately 6.78 MHz in one or more embodiments of the present application. InFIG. 10 , the measured values of the peak point C are approximately 5.21534 μs and approximately 11.15368 V, the measured values of the peak point D are approximately 5.217782 μs and approximately 10.11192 V, and the measured values of the peak point E are approximately 5.228352 μs and approximately 9.385039 V. - Referring further to
FIG. 13 , assuming that the reference peak voltage condition is RL=1Ω, when the temperature of the heat-generatingbody 40 continues to rise due to electromagnetic induction, the resistance value increases and VLC is sensed in the form of decreasing. In this case, theMCU 24 may stop the operation of thepower amplifier 30 in order to lower the temperature of the heat-generatingbody 40. In contrast, when thepower amplifier 30 stops operating for a certain period of time and the temperature of the heat-generatingbody 40 decreases, VLC is detected in the form of rising again, and at this time, theMCU 24 may operate the power amplifier again to maintain the temperature of the heat-generating body constant. Although the numerical value of the load resistor and the change amount of VLC have been described as an example in the above, it is clear that this is an example and is not limited to specific implementation examples. For example, for ease of operation of thesensing circuit 22, the VLC may be connected to thesensing circuit 22 through a normal peak detector circuit using a diode or operation amplifier among peak detectors. - In the electromagnetic induction heating apparatus implemented through one or more embodiments of the present application, a combination of the apparent resistance value estimation and LC resonance voltage sensing described above may also be used in order to actively sense the temperature of the heat-generating
body 40 and determine whether or not thepower amplifier 30 operates in response thereto. The performance of such an operation can be selectively controlled by theMCU 24 constituting the drivingunit 20, and can immediately control the operation time and time point of thepower amplifier 30 with respect to the change in temperature of the heat-generatingbody 40 that occurs when a user repeats an act of inhaling an electronic smoking article using the heat-generatingbody 40 so that the heat-generatingbody 40 for forming aerosol always maintains an optimal heating temperature. - As described in detail above, one or more embodiments of the present application provide an electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette, which can maximize a power utilization factor in a process of heating the aerosol-forming article of the electronic cigarette using a heat-generating body, can reduce the implementation and manufacturing difficulty of the apparatus, and can adaptively control a heating temperature of the heat-generating body, and a driving method thereof.
- Although the electromagnetic induction heating apparatus for heating the aerosol-forming article of the electronic cigarette and the driving method thereof have been described with reference to the specific embodiments, it is not limited thereto. Therefore, it will be readily understood by those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the present application defined by the appended claims.
Claims (13)
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KR1020220137553A KR20240057162A (en) | 2022-10-24 | 2022-10-24 | Electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette and driving method thereof |
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US20240138033A1 true US20240138033A1 (en) | 2024-04-25 |
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US18/345,826 Pending US20240237157A9 (en) | 2022-10-24 | 2023-06-30 | Electromagnetic induction heating apparatus for heating an aerosol-forming article of an electronic cigarette and driving method thereof |
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TWI692274B (en) | 2014-05-21 | 2020-04-21 | 瑞士商菲利浦莫里斯製品股份有限公司 | Inductive heating device for heating an aerosol-forming substrate and method of operating an inductive heating system |
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